Telephone and signaling circuit



(No Model.)

J. 0. WILSON.

TELEPHONE AND SIGNALING CIRCUIT. I No. 380,780. Patented Apr. 10, 1888.

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UNITED STATES PATENT FFICE.

JOHN owILsON, OF BOSTON, MASSAOHUSETTS, ASSIGNOR TO THE MUNICI- PAL SIGNAL COMPANY, OF PORTSMOUTH, NEW HAMPSHIRE.

TELEPHONE AND SIGNALING CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 380,780, dated April 10, 1888.

Application filed June 18, 1887. Serial No. 241,738.

To aZZ whom it may concern:

Be it known that I, JOHN 0. WILSON, of Boston, county of Suffolk, and State of Massachusetts, have invented an Improvement in Telephone and Signaling Oircuits,of which the following description, in connection with the accompanying drawing, is a specification,like letters on the drawing representing like parts.

This invention has for its object to provide an electric circuit with suitable Signal transmitting and receiving instruments, and also with telephonic instruments, whereby signals may be automatically transmitted and telephonic communication may be carried on at the same time without interference.

In accordance with this invention the main circuit is provided with one or more automatic signal-transmitters, and condensers are employed, one of which is placed in a shunt-circuit around each transmitter. An inductioncoil is employed at the receiving-station, the primary coil of which is included in the main circuit and the secondary coil in a secondary circuit,which latter circuit contains a polarized relay or other suitable receiving-instrument. The telephones are arranged to be connected with the main circuit in usual manner-as by the gravity-switch,for instance-and when all the signal-transmitters are at rest or in their normal condition the telephonic current passes over the main circuit through said signaltransmitters; but when any of the said signaltransmitters are setin operation the condenser, which is normally shunted out, is out into the main circuit momentarily, and the telephonic current will pass at such time through the condenser, thereby maintaining the continuity of the circuit for telephonic communication.

The drawing showsin diagram a main elec' tric circuit provided with suitable instruments so arranged in accordance wit-h this invention that signals may be automatically transmitted and telephonic communication carried on at the same time.

The main circuit a includes the main battery b, and to accomplish the ends herein desired is a metallic or round circuit. An automatic signal-transmitter is included in the circuit,it being understood that there may be one or several, as desired, said transmitter con- (No model.)

sisting of a brake-wheel, 25, contact-pen 26, and a suitable motor mechanism to rotate the brake-wheel, such a transmitter being shown in United States Patent NO. 320,032, granted to me. At the receivingstation an inductioncoil, (2, is provided, the primary coil of which is included in the main circuit and the secondary coil of which is included inasecondary circuit, 6, containing a polarized relay, f, or any other suitable receiving-instrument to receive the signals transmitted by the transmitters. A condenser, g, is placed in ashunt-circuit around each signal-transmitter, to be out into the main circuit when the line is opened by the said transmitter. A telephone, h, (one or several, as desired,) is connected with the main circuit a in any usual manner, as by a gravity-switch, for instance.

It will be seen that by employing a condenser in a short circuit around the signaltransmitter, whenever the line is opened by the transmitter, the continuity of the circuit is maintained for telephonic purposes,the current passing either through the transmitter direct or through the condenser by induction.

By employing an induction'coil to reproduce or repeat the signals the resistance of the line may be materially changed at will without in any way affecting the reception of the signals as, for instance, should several telephones be included in a closed circuit containing signal-transmitters and an ordinary receiving-relay, the high resistance would be sufficient to materially impair the adjustment of said relay or weaken the line nearly equal to a break, so that the armature of the relay would be retracted, while with the inductioncoil the number of telephones included in the line has no effect upon the accurate reception of the signals transmitted.

The arrangement of instruments herein shown is of especial advantage in police-signals, each signal-box containing the signaltransmitter, condensers in a shunt around it, and a telephone, and, as will be understood, oftentimes a signal is being transmitted from one box while an officer at another box is using the telephone, and to avoid possible interference and yet accurately receive the signal is the essential feature of this invention.

I claim transmitters or through the condenser, as and In an electric circuit,one or more automatic for the purpose set forth.

signal-transmitters and an induction-coil, one In testimony whereof I have signed my name of the coils of which is included in the said to this specification in the presence of two sub- 5 circuit and the other in a secondary circuit, scribing witnesses.

and a receiving-instrument in the said secondary circuit, combined with a condenser JOHN Q'WILSONT placed in a shunt-circuit around each signal- Witnesses: transmitter, and with telephones which op- BERNIcE J. NoYEs, TO eratein the circuit either through the signab F. L. EMERY. 

